European patent application EP 903 787 discloses alkoxyamines derived from β-phosphorylated nitroxides, which are used as free-radical polymerization initiators affording good polymerization control from (control of the masses, low polydispersities) in the case of numerous vinyl monomers: styrene and substituted styrenes, dienes, acrylic or methacrylic monomers, acrylonitrile.
The Applicant has found that reactive functions of ester type present on these alkoxyamines, and also derived functions such as an acid, acid salt or acid chloride function, allow chemical conversions to be performed easily either on the initial alkoxyamine or on the polymer derived from this alkoxyamine. The conversion of the initial alkoxyamine gives access to a novel alkoxyamine and allows the adaptation of the initiator to the intended application. In particular, this conversion may make it possible to synthesize polyalkoxyamines from a monoalkoxyamine. The conversion of the polymer derived from the alkoxyamine allows novel functional groups to be introduced or allows coupling reactions with another polymer. In particular, this conversion can give access to block copolymers involving blocks that are not available via free-radical polymerization.